Process for catalytic conversion of hydrocarbons



Oct. 27, 1942. L s. KAssEL 2,300,032

n PROCESS FOR CATALYTIC CONVERSION OF HYDROCARBONS Filed Nov. 30, 1939 2 Sheets-Sheet 1 Oct. 27, 1942. 1 s. KASSEL 2,300,032

` PROCESS FOR CATALYTIC CONVERSION oF HYDRocARBoNs y I Filed Nw. so, 1959 2 sheets-sheet 2 Patented Oct. 27, 1942 "UNITED STATES PATENT OFFICE raocEss Fon cATALmc coNvnnsioN F maocAnnoNs Louis S. Kassel, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application November 30, 1039, Serial No. 306,934

(ci. 19e-sz) 11 Claims.

olefin-free gasoline suitable for use as an avia-- tion base fuel.

The use ci various catalytic materials for the production of increased yields of high antiknock motor fuel has been practiced. Under certain conditions of operation involving temperatures in excess of approximately 850-900" F. and relatively low pressures, gasoline and gases containing large percentages of olen hydrccarbonsare produced by the catalytic cracking of hydrocarbon oils of higher than gasoline boiling range. The gasolinas produced are of good antiknock value, which makes them particularly desirable for use as motor fuel.

When such gasolines are subjected to the action of certain catalytic materials at relatively low temperatures, e, g., of the order of 50o-900 F., substantially olefin-free gasolines are obcomprises a process utilizing these steps to produce substantially saturated gasoline of desirable properties from hydrocarbon oils. i In one specific embodiment the present invention comprises a continuous process for converting hydrocarbon oil into high yields of substantially olefin-tree gasoline which consists in converting said hydrocarbon oil in a plurality of catalytic reactors serially arranged, wherein the repeated sequence of steps is carried out at each of said catalytic reactors, said sequence oi steps lcomprising a primary step of contacting olen- .containing distillate from a secondary step about to be described with acracking catalyst under tained accompanied by little or no change in the antiknock value. As a consequence the comblnation of these two processes oflers a good method of .producing substantially saturated gasoline v temperatures for producing adidtional yields of anoleiln-containing gasoline. p

Eventually the catalysts require regeneration in order to restore activity whichhas been decreased largely due to an accumulation of carbo- .naceous or hydrocarbonaceous deposits on their surfaces.v In reactivating the catalytic materials, temperatures of the-order of those employed in the high temperature cracking step or even higher are necessary, namely, approximately 900- '1500 F. A combination process using a low temperature processing step followed by a high tempeinture processing step and ilnally by 4reactivation, ofiers advantages. The present invention .65

conditions adequate to produce a substantially olefin-free gasoline, a secondary step of contacting said hydrocarbon oil with a cracking catalyst under conditions adequate to produce an oleiln-containing distillate for conversion in said primary step, a tertiary step oi reactivatingspent catalyst at a temperature level beginning at that of the secondary step, and a Quaternary step of completing reactivation while returning the temperature to the level of the primary step, the re actors operating in said primary and quaternary steps being maintained in heat exchange relationship with a circulating iluid heat exchange medium kept at a suitable relatively low temperature, and the reactors operating in said secondary and tertiary steps being maintained in heat exchange relationship with a separate circulating uid heat exchange medium kept at a suitable relatively higher temperature, recovering the gasoline from said primary step and re- '35 turning a portion of insuillciently converted oil tofsaid primary and/or secondary steps for further conversion.

The two temperature levels are achieved and controlled by the use of two separate circuits of heat exchange fluids so arranged that each catalyst region may be brought into heat exchange relationship with the iluid in either circuit. One method of accomplishing thisis illustrated in Fig. 2, which will .be explained in detail later in the specifications. The materials which may be used as heat exchange media include low meltingmetals or' alloys, alkali metal hydroxides, mixtures of salts melting below 45o-500 F., etc.

Fig. 1 is an illustrationof a process hook-up involving the use of the various temperature levels contemplated for processing and reactivation. The illustrations are diagrammatic and represent one embodiment of the principle involved, and should not be interpreted as limiting the invention to the exact apparatus or equipment shown. Numerous types of reactors or variations of the type shown may be employed., and these are understood to be included within the scope of the present invention,

Fig. 2 illustrates diagrammatically a heat exchange system whereby the operation illustrated in Fig. 1 may be accomplished, reactors I, 2, 3 and 4 in both Fig. 1 and Fig. 2 being identical.

Figs. 3, 4, 5, 6 and 7 illustrate diagrammati` callyvariations in the .setting of the respective switching valves illustrated in Fig. 2.

IThe apparatus consists essentially of four' manifolded reactors. The reactors may comprise any suitable type, of which that illustrated is a simple diagrammatic representation consisting of one or more catalyst tubes or chambers disposed in a jacket or shell through which a heat exchange medium can be circulated. The entire operation involves a repeated cycle of four.

through line 5, valve 6, pump 1, line 8, valve 9 and line I to coil 4Il, which is disposed in heater I2, and wherein it is-heated to a temperature within the range of approximately 850120Il0 F. The oil then passes through line I3 and valve I4 to line I and valve I6, entering the catalyst tube l1 which is a part of reactor 2. The catalyst tube contains a suitable cracking catalyst and is disposed in shell I8 equipped with inlet and outlet lines i9 and 20 which provide a means for circulating a heat exchange medium around the reactor tube. It is understood that tube I1 may consist of a reaction chamber or a multiplicity of manifolded tubes containing catalyst. As vpreviously mentioned, the hook-up for circulating the heat exchange medium is illustrated in Fig. 2. The reaction products leave reactor 2 through line 2| and valve 22, passing by way of line 23 to fractionator 24. Gaseous products are removed through line 25 and valve 26. These gases contain polymerizable olefin hydrocarbons which may be-separately processed by known methods to produce high antiknock motor fuel. A residual oil may be withdrawn. and removed from the system through line 21 and valve 28.

The 'insufliciently converted oil is passed through line 29, valve 30, line 3l and valve 3l',

which joins with line I0, and -is thus recirculated to the cracking step. The gasoline from fractionator 24 is passed through line 33 and valve 34, pump 31 and valve 38 to coil`35, which is disposed in heater 36. The heated oil passes through line 39 and valve 40 to line 4I and valve 42 and thence into reaction tube 43, which is disposedl in reactor I, which is similar to reactor 2 and is equipped with shell 44 and inlet and outlet lines 45 and 46 for circulating heat exchange fluid. 'Ihe reaction products are withdrawn through line .41, valve 48 to line 49 and passed thence to fractionator 50. Gaseous products may be removed through line 5I and valve 52. Gasoline which is substantially saturated and which may be used as `an aviation base fuel is removed through line 53 and valve 54.

Avalve 65 to line 66. 'temperature in reactor 3 is broughtback to the drawn. through line |01 and valve |08. The temperature at which reactor I is operated is within vthe range of approximately 50G-900 F. Re-

activation gases are introduced through line 51, line 58, valve 59, entering tube 60 which is disposed in reactor 3. This reactor is similar to I and' 2, being equipped with shell 6I and inlet and outlet lines 62 and 63 for the circulation of neat exchange uid. The reactivation gases leave the system throughline 64, valve 65, line 66 and may be vented to the atmosphere, or a portion of the gas may be recirculated by means not' shown. Another portion of reactivation gas passes through line 61, valve 68 to tube 69, which is disposed in reactor 4, similar to reactors I, 2, and 3, and equipped with shell 10 and .inlet and outlet line 1l and 12 for the circulation of heat exchange medium. The temperature of this reactor is decreased during the reactivation step to the level of reactor I. The temperature of reactivation in reactor 3 begins atl approximately gurl. I n this phase the products of the higher temperature catalytic cracking from line 39 are passed through lineV 15 and valve 16 into reactor tube 69 in reactor 4 at a temperature of 50G-900 F; and thence through line 11 and valve 18 to line 49, fractionator I50, and then as previously described. The raw oil charging stock from line I3, together with the recycle stock, is passed through line 19 and valve 80 to reactor I which is being operated in the high temperature range of G-1200 F. and is then passed through line 8l and valve 82 to line 23. At the same time, reactivation gases are passed from line 51 through line 83 and valve 84 to reactor 2 and thence through line 85 and valve 86 to line 66. Reactivation is carried out at a temperature of approximately 900-l500 F. during this stage of operation. Reactivation gases from line 51 are passed also through line 58 and valve 59 to reactor 3 and thence through line 64 and During this interval the approximate range of 50G-900 F. After a suitable interval, the valve settings are changed to those for the third phase of the cycle, in which reactor 3 is processing in the lower temperature range, reactor 4 is processing in the higher temperature range, reactor I is being reactivated in the higher temperature range and reactor 2 is being returned to the lower temperature range. This is accomplished by passing the raw oil charge from line I3 through line 61 and valve 88A to reactor 4, which is processing at a temperature of 800-1200 F. The reaction products are passed through line 89' and valve 90 to line 23 and fractionator 24. At the same time the products of the high temperature catalytic cracking from line 39 are passed through line 9| and valve 92 to contact with the freshly reactivated catalyst in reactor 3 and thence by means of line 93 and valve 94 to line 49 and fractionator 50. Reactivation gases from line 51 enter reactor I through line 95 and valve 96 and are exhausted through line 91 and valve 98 .toline 66. Reactivation is carried out at the higher temperature level during this period. At the same time reactivation gases from line 51 are passed through line 83 and valve 84 to reactor 2 and thence are exhausted through line 85. valve 86 and line 66. returnedrto the lower range during this step. After a suitable interval the valve settings are switched -to those of the fourth phase of the cycle in which charging stock from line I3 is passed through line 99 and valve |00 to reactor `3, which is operated in the higher temperature cracking range. The products pass throughline IIII and valve |02 to line 23and thence to fractionator 24. passed'through line |83 and valve`|04 to reactor 2 which contains freshly reactivated catalyst. The reaction products are removed through line III5, valve |06 ,and line 49 to fractionator 50. At the same time reactivation gases from line 51 are introduced into reactor 4 through line 61 and valve 68 and removed through line 13, valve 14 and line 66. Simultaneously reactivation gases pass through reactor. I to line 95, and I valve 96 and*Y are exhausted through line 91, valve 9 8 and line 66, the temperature of reactor I being brought back to thelower 4temperature range during this step. After a suitable interval the may be used, thereby permitting the time during which a reactor remains at any particular proccondition to ,be indeessing or reactivation pendently fixed.

According to one alternative within the scope of the present invention, a part or all of the oil from line 3| which is made up of insufiiciently The temperature isA The hydrocarbons from line 38 are passedthrough the catalyst mass.' 'I he medium passesthrougn une z4,sw1tchm`gva1ve :sito une 1 where it is -piclr'ed up by pump 8 and recircuheat exchange system is introduced through line A26 and valve 21, passing into line 28 and pump 29. The molten mixture passes through exn shoum' v converted oil from fractionators 24 and 50 may.

be passed through line 32 and valve 32 to line 33 and thence to 'the lower temperature processing step for conversion into substantially oleiin-free gasoline.

Certain pumps,v heat exchangers, condensers, stabilizers and other auxiliary equipment necessary to the operation of such a process have been omitted in interests of simplifying the drawings. f

Referring to Fig. 2, heat exchange media which may comprise any suitable liquid material such as mitures of molten salts, metals or metal alloys and the like, is introduced through line 5,

valve 6, line 1, pump 8, and passes through exchanger 9 wherein it may be heated or cooled as desired.' When the medium is first introduced it is heated to the desiredreaction temperature.`

The medium passes through line I8 to switching valve II and thence to 'reactor I, entering through'line I2 intoshell I3. Reactor I' contains catalyst tube I4, which as previously noted. may comprise reaction. chambers or a pluralitvof manifolded tubescontaining catalyst particles disposed therein. Reactor I in this cas`ev is being used to process hydrocarbon oil in the lower` temperature range of o-900 F. The* medium passes-through line I5 and switching valve I6, line I1, valve I8, line I8, switching valve 20, line 2| toshell 22-0f reactor 4. This reactor is sim- -ilarfto reactor I and containsV catalyst tube 23. In this step ofthe processing cycle, reactor 4 changer 30 whichmay be'a heater or cooler as is necessary for' the particular operation being carried .out..- The salt passes through switching valve II, line 3i, switching valve I6, -line 32 to reactor 2, which is similar to reactors I and 4 and contains catalyst tube 33' disposed in shell 34. Reactor 2 is atthis point being used to process hydrocarbon oil in the high temperature range, namely, 80G-1200 F. The medium leaves reactor 2 through. line 35, passes through switching valve I8,l line 36 to reactor 3 which is similar to the other catalytic reactors and containstube 31 disposed-'in shell 3 8. Reactor 3 is being reactivated in the higher 4temperature range, namely, 900-l500 F. The medium leaves the reactor through line 39, switching valve 20, line 40, switching valve 25, returning through line y4| to pump 29 whereby it is recirculated.

The switching valves are four-Way valves which may be set in the positions indicated in Fig. l when voperating as described. When changing the operation, it is necessary to change the valve settings in a manner indicated in Figs. 3, 4, 5, 6 and 7. In this manner, the temperature can be regulated for the successive processing and regenerating steps described and illustrated in Fig. 1. According to the valve setting justdescribed, reactor I is processing at the lower temperature, reactor 2A processing at the higher temperature, reactor 3 reactivatin'g at the higher temperature and reactor 4 reactivating at the lower temperature.

When the operation is shifted in the course of the regular cycle so that reactor I is processing. at the higher temperature, reactor 2 regenerating at the higher. temperature, -reactor 3 regenerating at the lower temperature and reactor 4 processing at the lower temperature, the valves are in the following positions: valve II as in Fig. 3; I6 as in Fig. 4; I8 as in Fig. 5; 2n as in Fig. 6;

and 25 as in Fig.2.

`is being returned fromthe higher temperature -l In the next regular step the operation, re actor I is reactivating at the higher temperature, reactor 2 reactivatingv at the lower temperature, reactor 3 processing at the lower temperature and reactor 4 processing at the higher temperature, the valve positions are valve II asin Fig. 3, valves I6, I8 and 2 0 as in Fig. 2, and valve 25 as in Fig. 7.

In the next step of the cycle wherein reactor I is reactivating at the lower temperature, reactor 2 processing at the lower temperature, reactor 3 processing at the higher temperature, and reactor,4 reactivating at th higher temperature, the valve positions are, valve II as in Fig. 2, and

valves I6, I8, 28 and 25 as in Figs. fi, 5, 6, and 7, respectively.

The cycle is completed when the valves are switched to the original position whereby reactor is processing at the lower temperature, reactor 2 processing at the higher temperature, reactor 3 vreactivating at the higher temperature, and reactor 4 reactivatingt the lower temperature,

Vwith.tlrieAf-Vialvves in posltionsjllustrated in Flgf2.

namely, E500-900?J F., reactivation lgases being The following example is given to illustrate the usefulness and practicability of my invention when using a cracking catalyst under conditions to produce high yields of substantially saturated motor fuel. The example should not be construed as limiting the invention to the materials, apparatus or conditions indicated.

A catalyst comprising essentially precipitated silica having deposited thereon a minor proportion of precipitated alumina and precipitated zirconia was made into pellets and placed in a series of four catalytic reactors similar to those described in the foregoing specifications. A Midcontinent gas oil was cracked in the manner described in the specifications using the following conditions:

The lower temperature cracking step was carried out at 750 F. and a pressure of 100 pounds per square inch. The charge to this step comprised the catalytically cracked gasoline having added thereto approximately 25% of the recycle oil. The higher temperature cracking step was carried out at 950 F. and a pressure of approximately 50 pounds per square inch. The charge comprised a combined feed consisting of the raw oil plus the remaining portion of the insufficiently converted oil from both the high and low temperature cracking steps. A small portion of residual oil from the higher temperature cracking step was continuously withdrawn from the system. The high temperature reactivation was carried out at a maximum temperature of l350 F. and the low temperature reactivation began atI obtained. The octane number was 78, which was increased to 95 upon the addition of 6 cc. of tetraethyl lead per gallon. In addition, 14% of polymer gasoline was produced, a large portion of which could be hydrogenated to produce isooctane. Thus the total yield of gasoline amounted to 83%, of which a major portion was suitable for use as an aviation base fuel.

I claim as my invention:

1. A continuous catalytic process for converting normally liquid hydrocarbons into high yields o'f desirable products including substantially oleiin-free high antiknock distillate suitable for use in aviation fuel which comprises converting said hydrocarbons in a plurality of substantially iden- Itical conversion zones serially arranged wherein the flow of hydrocarbons to, and the Withdrawal of reaction products from the entire group of said conversion zones is substantially constant, and wherein the repeated sequence of steps is carried out in each of said conversion zones in a cyclic mannercomprising a primary step wherein a stream of olefinic gasoline is contacted with a freshly reactivated catalyst under conditions of temperature and pressure adequate to produce a substantial yield of substantially saturated high octane distillate, a secondary step in which a separate stream of hydrocarbons heavier than gasoline is contacted with partially spent catalyst from the primary step at a relatively higher temperature to produce a substantial yield of relapartially reactivated by treatment with oxygencontaining gas at a temperature substantially higher than that suitable for the primary step, a quaternary step in which reactivation is completed while the catalyst temperature is being restored to that suitable for said primary step, recovering the gasoline formed, and returning a portion of the insufficiently converted oil for fur ther conversion.

2. .A continuous process for converting hydrocarbon oil into high yields of substantially olefinfree gasoline which comprises converting said hydrocarbon oil in a plurality of conversion stages serially arranged wherein the repeated sequence of steps is carried out at each of said conversion stages, comprising a primary step of contacting an olefin-containing distillate produced as hereinafter described with a cracking catalyst under conditions of temperature and pressure adequate to effect substantial conversion thereof to substantially olefin-free gasoline, a secondary step of contacting hydrocarbon oil heavier than said distillate with said cracking catalyst under conditions of temperature and pressure adequate to effect substantial conversion thereof into olefincontaining distillate for conversion in said primary step, a tertiary step of partially reactivating said cracking catalyst used in said primary and secondary steps with an oxygen-containing gas at a temperature in excess of that used for processing in said primary step, and a quaternary step of completing reactivation of said cracking catalyst with an oxygen-containing gas while returning the temperature to that required for processing in said primarystep, recovering the gasoline from said primary step, and returning a portion of the insufficiently converted oil for further conversion.

3. A continuous process for convertingvhydrocarbon oil into high yields of substantially olefinfree gasoline which comprises converting said hydrocarbon oil in a plurality of conversion stages serially arranged wherein the repeated sequence of steps is carried out at each of said conversion stages, comprising a primary step of contacting olefin-containing distillate produced as hereinafter described with a cracking `catalyst under conditions of temperature and pressure adequate to effect substantial conversion thereof to substantially olefin-free gasoline, a secondary step of contacting hydrocarbon oil heavier than said distillate with said cracking catalyst under conditions of temperature and pressure adequate to effect substantial conversion thereof into olefincontaining distillate for conversion in said primary step, a tertiary step of partially reactivating said cracking catalyst which has been spent by use in said primary and secondary steps with an oxygen-containing gas at a4 temperature in excess of that used for processing in' said primary step and a quaternary step of completing the reactivation of said cracking catalyst with an oxygen-containing gas while restoring the temperature to that required for processing in said primary step, maintaining those conversion stages operatingy in said primary -and quaternary steps in heat exchange relationship by means of a circulating fluid heat exchange med ium, maintaining those conversion stages operating in said secondary and tertiary steps in heat exchange relationship by means of a separate circulating fluid heat exchange medium, Yrecovering the gasoline from said primary step, and returning a portion of the insuiciently converted oil for further conversion.

4. The process set forth in claim 1 wherein the cracking catalyst is selected from the group consisting of silica-alumina, silica-zirconia and silica-alumina-zirconia.

5. The process set forth in claim 1 wherein the primary step is carried out at a temperature within the range of approximately -500-900 F. and a pressure of approximately 50-1000 pounds per square inch and the secondary step is carried out at a temperature within4 the range of approximately 900-1200 F. and a pressure of substantially atmospheric to 100 pounds per square inch. Y

6. A continuous process for converting hydrocarbon oil into high yields of substantially olefin-free gasoline which comprises converting said oil in a plurality of catalytic converters serially arranged wherein the repeated sequence of steps is .carried out at each of said catalytic reactors, comprising a primary step of contacting an olefin-containing gasoline mixed with insufficiently converted oil produced as hereinafter described, with a cracking catalyst under` conditions of temperature and pressure adequate to effect substantial conversion thereof into substantially olefin-free gasoline, a secondary step of contacting hydrocarbon oil heavier than gasoline with said cracking catalyst under conditions of temperature and pressure adequate to produce substantial conversion thereof 'into oleiin-containing gasoline and insuillciently converted oil for conversion in said primary step, a tertiary step of partially reactivating said cracking catalyst used in said primary and secondary steps with an oxygen-containing gas at a temperature in excess of that used for processing in saidprimary step and a quaternary step of completing the reactivation of said cracking catalyst with an oxygen-containing gas, while returning the temperature to that required for processing in said primary step, maintaining said primary step and said quaternary step in heat exchange relationship by means of a circulating fluid heat exchange medium,.V maintaining said the reactivation of said cracking catalyst with an oxygen-containing gas while returning the temperature to that for processing in said primary step, recovering the gasoline from said primary step, returning a portion of the insuiiiciently converted -oil to said secondary step, maintaining thel reactors operating in lsaid primary and said quaternary steps in heat exchange relationship by means of a primary heat exchange system, and maintaining the reactors operating in said secondary and .tertiary steps in heat exchange relationship by means of a second heat exchange system.

8. In the catalytic conversion of hydrocarbon oils wherein a body of cracking, catalyst is employed in an operating cycle including processing and regenerating steps, th'e method which comprises contacting olefinic gasoline with a body of crackingcatalyst at a temperature of about 500- 900 F. whereby to produce substantially saturated gasoline, then contacting hydrocarbon oill heavier than gasoline with said body at temperature in excess of 900 F., thereby forming olefinic gasoline, then partially reactivating said body of cracking catalyst by treatment thereof with oxygen-containing gas at a temperature in excess of 900 F., completing the reactivation of the catalyst body at a temperature in the approximate range of 500-900" F., and thereafter repeating the aforesaid cycle on said body of catalyst.

9. The'process as defined in claim 8 further characterized in lthat oleiinic gasoline produced from said oil heavier than gasoline is supplied to the mst-mentioned conversion step.

10. The process as set forth in claim 1 wherein the cracking catalyst comprises .essentially an acid-treated clay.

` l1. A continuous process for-converting hydrocarbonzoil into high yields of substantially olen- 'free gasoline-which comprises converting said hyi -drocarbon oil in a plurality of conversion stages secondary step and said tertiary step in heat exchange relationship by means of a separate circulating fluid heat exchange medium, recovering the gasoline from said primary step and withdrawing a minor portion of residue unsuitable for further conversion.

'1. A continuous process for converting hydrocarbon oil into high yields of substantially olenn-free gasoline which comprises converting said hydrocarbon oil in a plurality of catalytic reactors serially arranged wherein a repeated sequence oi' steps is carried out at each of said reactors. comprising a primary step of contacting olefin-containinggreaction products -of catalytic cracking produced as hereinafter described with a cracking catalyst under conditions of temperature and pressure adequate to effect substantial conversion thereof into Vsubstantially olenn-free gasoline, a secondary step of contacting hydro-v carbon oil heavier than gasoline with said ,cracking catatyst under conditions of temperature and pressure adequate to effect substantial conversion thereof to olefin-containing reaction prodserially arranged wherein the repeated sequence of steps is carried out at each of said conversion stages comprising a primary step of contacting olefin-containing Agasoline produced as hereinafter`described with a cracking catalyst under conditions of temperature and pressure adequate to effect substantial conversion'thereof into substantially olefin-free gasoline, a secondary step of contacting hydrocarbon oil heavier than gasoline with said cracking catalyst under conditions of temperature and pressure adequate to effect substantial conversion thereof into olefin-containing gasoline for conversion in saidv primary step, a tertiary step of partially reactivating'said cracking catalyst used in said primary and secondary steps with anoxygen-containing gas at a temperature in excess of that used for processing in.

said primary step, and a quaternary step `of completing the reactivation of said catalyst by treatment with an oxygen-containing gas while returning the temperature to that required for processing in said primary step, recovering the gasoline from said primary step, passing the part of the reaction products from said primary step boiling above the gasoline range to said secondary step, and recycling a portion of the insum'ciently converted oil from said secondary step.

mms s. massa. 

